CAMP WOOD, Tex. -- Big chunks of rock, not water, fill the dry bed of the Neuces River which slithers through the Rawhide Mountains in Texas as a tough Trail grade rendition of Toyota's revamped and enlarged 4Runner sport utility wagon -- packing heavy firepower and applying traction to every nubby 265/70R17 off-road tire -- muscles its way in bump-bump-bump increments across so many stones.
The wagon doesn't vacillate from our mission to ford the dry wash, although its front wheels, floating independently in a double wishbone design, articulate way-up and way-down to crawl through the rocky sluice.
From a driver's vantage strapped in a form-fitting bucket of 4Runner's expanded cabin, however, we hardly notice the wild wheel gyrations because this vehicle rides surprisingly steady over rough terrain.
That smooth but rock-solid ride quality is the result of a ladder-format platform with twist-resisting boxed steel side rails which forms a rigid foundation to support a welded steel body.
Toyota constructs the redesigned 2010 4Runner SUV in three grades (SR5, Trail, Limited) with a couple of powertrain choices and rear-wheel two-wheel-drive (2WD) or four-wheel-drive (4WD) traction.
The 4WD SR5 and Trail editions employ a lever-operated two-speed part-time 4WD mechanism with neutral position.
On the 4WD Limited there's a full-time 4WD system with Torsen limited-slip locking center differential controlled with a three-mode switch mounted on the center console.
4Runner's suspension system consists of the independent double wishbone design up front with coil springs over gas shocks and a solid axle in back set in four-link scheme also with springs on shocks.
Standard on each 4Runner is Toyota's Star Safety System, which includes an anti-lock brake system (ABS) with electronic brake-force distribution (EBD) and electronic brake assist (EBA), plus vehicle stability control (VSC).
4Runner in 2WD format stocks a limited-slip differential (LSD) tied to a sophisticated traction control system (TRAC) to manage the grip of both rear wheels on slippery surfaces.
The 4WD editions also carry electronic four-wheel traction control, labeled active traction control (A-TRAC).
4Runner Trail grade adds Toyota's Kinetic Dynamic Suspension System (KDSS) which disconnects stabilizer bars to allow for more vertical travel of the axle and better suspension articulation when rolling over dicey terrain.
Toyota's Crawl Control (CRAWL) device -- standard on Trail grade -- is an electro-mechanical system that works with the transfer case set in low range regulating engine speed and output as well as brakes to send the vehicle forward or backward at a low speed. It incorporates downhill assist control (DAC), which aids in a steep descent without driver intervention.
Further, a new Multi-Terrain Select system allows the driver to dial in the amount of wheel slip permitted to match the terrain.
Large diameter wheels and tires were added to improve off-road performance and also enhance 4Runner's truck-based characteristics.
A standard set of wheels on 4Runner measures to 17 inches in diameter (20 inches for Limited), which positions the chassis ground clearance at 9.6 inches for 4WD or 9.0 inches for 2WD.
And with wheels set on corners of the structure, the SUV scores solid numbers for approach/departure angles (32 degrees/26 degrees for 4WD Trail grade).
Every 2010 4Runner wears new bumpers and broader shoulders with square fender flares, fresh designs for headlamp and taillamp assemblies, and a squared-off tail bumper and rear door.
The SR5 grade also gets overfenders and mud guards plus a roof rack for hauling extra gear.
The Trail grade with high ground clearance carries a hood scoop, black side mirrors, bumper guards front and rear and dark smoke treatment on lamps.
Both Limited and SR5 trims add premium appearance items like chrome plating the front grille, foglamp bezels and roof rack, and color-keyed front and rear overfenders and side skirts.
Toyota offers choices for powertrains.
The base 2WD 4Runner SR5 model come with a 2.7-liter in-line-four engine with dual overhead cams (DOHC) and Toyota's intelligent variable valve timing (VVT-i) coupled to a four-speed electronic automatic transmission.
The plant produces 157 hp at 5200 rpm and torque of 178 lb-ft at 3800 rpm.
It runs on 87-octane regular unleaded gasoline stowed in a 23-gallon fuel tank and shows EPA fuel economy figures up to 23 miles per gallon for highway travel.
All other 4Runner models draw from a new dual-cam 4.0-liter aluminum-block six-pack rigged with VVT-i.
Power numbers increases with the new engine design -- it pumps 270 hp at 5600 rpm and 278 lb-ft of torque at 4400 rpm.
Transmission for the V6 is Toyota's five-speed electronically-controlled automatic.
The spacious passenger compartment in 4Runner shows fabric seats for SR5, water-resistant fabric-trimmed seat material for Trail grade and plush leather in the Limited with power controls plus internal heaters for the front bolstered buckets.
A second-row bench divides 40/20/40 and the seatbacks fold flat.
Optional third-row seats for SR5 and Limited are larger and more supportive, and access improves via the one-touch walk-in function added to second-row seats.